压敏型脲醛树脂微胶囊的研制

Preparation of Pressure Sensitive Urea Formaldehyde Resin Microcapsules with SMA as Emulsifier

应用自制的脲醛预聚树脂，以SMA作为乳化剂，采用原位聚合法研制出了压敏型脲醛树脂微胶囊。实验确定的最佳制备工艺条件为：尿素与甲醛的物质的量的比为1：2．0，pH值3—4，温度70℃，保温6h。研究结果表明，微胶囊对芯材的包封较好，粒径分布均匀集中，形态为单壁单核，囊壁密封性好。

The pressure sensitive urea formaldehyde resin microcapsules were prepared by using the in situ polymerization and the optimal preparation condition was studied. The styrene maleic anhydride copolymer （SMA） was used as the emulsifier first time to replace the EMA31 that has already not been produced worldwide, and the urea formaldehyde pre-resin prepared in our lab was used as the wall material. The microcapsules with the wall materials of urea formaldehyde resin and the core material of leuco dye CVL were used in carbonless copy paper. The experiment illustrated that the wall of microcapsule consisted of the UF pre-resin and the UF resin had been synthesized in the process of preparation, the CVL was encapsulated into the microcapsules, the particle size distributions was narrowed, the particle morphology was single core and single wall, the wall was hermetically sealed. In the process of preparation all of raw materials were made in domestic chemical factories. The preparation process was simple; the products can be used for the carbonless carbon paper. The results indicated that the influencing factors on the preparation of the microcapsules mainly are the temperature, pH value, reaction time and the mole ratio of urea and formaldehyde.